Disposable vacuum/peristaltic pump cassette system

ABSTRACT

A microsurgical irrigation/aspiration system is provided, including a controller having a pump roller head, actuators for occluding fluid lines, a suction sensor, and means for mounting a pump cassette. The system cassette is suitable for mounting on the controller and has an opening with a pump segment passing along an arcuate wall of the opening. When the cassette is mounted on the console, the roller head is engaged in the cassette opening and compresses the pump segment against the arcuate wall. An infusion line passes through the cassette and is occludable by one of the actuators, and a vent line connected to the pump segment is occludable by a second actuator. A suction sensing port on the cassette couples with the suction sensor in the controller. In an alternate embodiment, a cassette is disclosed within which both vacuum and peristaltic pumping is possible. Latching may be accomplished by a plunger attached to the sensory port of the cassette.

This is a continuation of application Ser. No. 253,801, filed Oct. 5,1988, now U.S. Pat. No. 5,125,891, which is a continuation-in-part ofSer. No. 43,120 entitled "Disposable Peristaltic Pump Cassette System",filed Apr. 27, 1987, now U.S. Pat. No. 4,798,580.

This invention relates to peristaltic pumps and, in particular, toperistaltic pump systems with disposable cassettes adaptable for use inophthalmic microsurgery. In addition, the present invention particularlyrelates to vacuum pump systems incorporated with the peristaltic pumpsystem using disposable cassettes adaptable for use in ophthalmicmicrosurgery.

In ophthalmic microsurgery, commonly employed surgical instruments suchas electro-mechanical or pneumatically driven cutters andphacoemulsification instruments require a source of liquid to infuse asurgical site, and a source of negative pressure to evacuate theinfusion liquid and debris from the site. Systems which perform theseliquid flow functions for microsurgical instruments are commerciallyavailable, and are known as infusion/aspiration systems. One such systemwhich has gained widespread acceptance is the SITE TXR® system, thefundamental principles of which are described in U.S. Pat. No.4,493,695. That patent describes a cassette assembly which mounts on amodular control console. The control console interfaces with thecassette to provide a source of vacuum for a suction line connectedbetween the cassette and the surgical instrument, and control means forcontrolling the application of suction and infusion fluid for theinstrument. Connected to the cassette and in fluid communication withthe suction line is a collection bottle which collects the aspiratedliquid and debris from the surgical site. For each surgical procedure anew cassette and collection bottle are mounted on the console and thecassette and bottle are disposed of after the procedure, therebyinsuring that a completely sterile fluid system is used for eachprocedure.

The console of the patented system includes a diaphragm vacuum pumpwhich provides the source of suction for the cassette. Another mechanismwhich is capable of supplying a negative fluid pressure for medicalapparatus is the peristaltic pump, which is desirable for its ability toprovide liquid suction. A peristaltic pump generally includes a motordriven head containing a number of rollers. A section of collapsibletubing is securely mounted around the roller head by a clampingmechanism. As the roller head turns, individual rollers sequentiallycompress the tubing and squeeze liquid through it in the direction ofrotation of the roller head.

When a peristaltic pump is used in an infusion/ aspiration system, thepreviously described need for sterility of the fluid system is stillpresent. It is desirable for a disposable system for the peristalticpump to provide all of the fluid control required in aninfusion/aspiration system. The disposable system should be economicalto produce so it can be disposed of after use without incurring a largeexpense. The disposable system should also be compact so as to require aminimal storage area in a hospital or other medical facility.

In accordance with the principles of the present invention a peristalticpumping system for infusion/aspiration procedures is provided whichincludes a disposable pump cassette. The system includes a console witha roller head, means for mounting the cassette over the roller head, andinterrupter bars for occluding the tubing and flow of infusion fluid inthe cassette. An infusion fluid line passes through the cassette, and isaligned with an interrupter bar in the console. The interrupter bar isselectably controlled to control the flow of infusion liquid to thesurgical site. A suction line is connected to the cassette and is curvedaround an arcuate opening in the cassette which is located around theroller head. Rotation of the roller head will thereby draw liquid fromthe surgical site through the suction line.

In a preferred embodiment of the present invention, a pressure sensingport is connected to the suction line of the cassette. The pressuresensing port connects to a pressure sensor within the console, whichmonitors the suction pressure and supplies feedback to control the pump.A constructed embodiment of the cassette of the present invention isvery compact, measuring about 3.5 inches by 4 inches by one-half inchthick, and is economical to manufacture and assemble.

In accordance with the principles of the present invention, there isalso disclosed a dual peristaltic pumping/diaphragm vacuum system forinfusing/aspiration procedures which includes a disposable pumpcassette. The system includes a console with either a peristaltic heador a vacuum diaphragm head, wherein either can be positioned in place inorder to accept the disposable pump cassette. There are means formounting the cassette over the pumping system, and interrupter means foroccluding the line in the cassette. An infusion fluid line passesthrough the cassette, and is aligned with the interrupter means in theconsole. The interrupter means can be selectively controlled to controlthe flow of infusion liquid to the surgical site.

The suction line is connected to the cassette and is curved around anarcuate opening in the cassette which is located around the pumpingsystem. Where peristaltic pumping is used, the suction line is curvedaround the arcuate opening in order to accept the roller heads of theperistaltic pump. Where vacuum suction is used, the suction line opensinto the vacuum diaphragm system. In either event, the pump systems willdraw liquid from the surgical site through the suction line.

In this preferred embodiment of the present invention, a pressuresensing port is also connected to the suction line of the cassette. Theport connects to a pressure sensor within the console, which monitorsthe suction pressure. A constructed embodiment of this cassette of thepresent invention is also very compact, measuring about 4 inches by 4inches by 1 inch thick, and is also economical to manufacture andassemble.

In the drawings:

FIG. 1 illustrates a peristaltic pump module constructed in accordancewith the principles of the present invention;

FIG. 2 is a front plan view of a peristaltic pump cassette suitable foruse with the module of FIG. 1;

FIG. 3 is a rear plan view of the cassette of FIG. 2;

FIG. 4 is a bottom plan view of the cassette of FIG. 1;

FIG. 5 is an internal view of the back half of the cassette of FIG. 2taken along line 5--5 in FIG. 4;

FIG. 6 is a view of the junction block and associated tubing segmentsshown in FIG. 5;

FIG. 6a is a cross-sectional view taken along line 6a-6a of FIG. 6;

FIG. 7 is an internal view of the front half of the cassette of FIG. 2taken along line 7--7 in FIG. 4;

FIG. 8 is a side view of the cassette of FIGS. 2-7 when mounted on themodule of FIG. 1;

FIG. 9 is a front view in perspective of a second preferred embodimentof the cassette of the present invention interacting a peristaltic pumpmodule;

FIG. 10 is a schematic view of the cassette of a second preferredembodiment of the present invention when using a peristaltic pumpmodule;

FIG. 11 is an internal view of the back half of the cassette of FIG. 9taken along line 11--11 of FIG. 9;

FIG. 12 is a schematic view of an alternate use of a peristaltic pumpwith the cassette of the present invention;

FIG. 13 is a schematic view of the cassette of the present inventionwhen used with a conventional vacuum pump system;

FIG. 14 is a schematic of an alternate use of the cassette of thepresent invention with a conventional vacuum pump system; and

FIG. 15 is a front plan view of a console for use in conjunction with asecond embodiment of the cassette of the present invention as seen inFIG. 12.

Referring to FIG. 1, a peristaltic pump module 10 constructed inaccordance with the principles of the present invention is shown. Aconstructed embodiment of this module has been built as a modular add-onto the SITE TXR® system. This mainframe system includes a chassis whichcan accommodate a number of modules that perform different functions forthe ophthalmic surgeon, including the control of surgical cuttinginstruments and infusion and aspiration. The module shown in FIG. 1 isrepresentative of one of these modules which provides infusion andperistaltic pump aspiration.

On the front panel 11 of the module are a number of controls anddisplays. A concentric switch includes a center knob 32 which turns themodule on and is adjustable to set the maximum suction level to beapplied by the peristaltic pump. As the knob 32 is adjusted the numbersdisplayed by the preset vacuum display 34 will vary to indicate thesetting of the maximum vacuum. The outer knob 36 is adjustable to one ofthree settings: mm Hg, in. H₂ O, and in. Hg. The setting of knob 36illuminates one of three corresponding lights 38a, 38b, or 38c, whichinform the user as to the units in which the vacuum measurements arebeing displayed by displays 34 and 40. The display 40 constantlydisplays the vacuum level at the inlet (suction) line to the peristalticpump. A pressure sensor accesses the suction line through a port 22.

Three pushbuttons 42a, 42b, and 42c provide control of the liquidinfusion line. When the "auto" pushbutton 42c is depressed, the infusionline is opened automatically whenever a control pedal (not shown) isdepressed to start the pump, and is automatically occluded by theextension of a solenoid actuated interrupter bar through opening 26 whenthe control pedal is released. The other two pushbuttons provide manualcontrol of the infusion line. When "closed" pushbutton 42a is depressed,the interrupter bar extends to occlude the infusion line, and when"open" pushbutton 42b is depressed the interrupter bar retracts to openthe line The control functions of pushbuttons 42a and 42b operateindependently of the control pedal.

The pump speed, and hence the rate at which the vacuum level isdeveloped by the pump, is set by depressing one of pushbuttons 30. Eachpushbutton controls the suction rate, as measured in cubic centimetersof flow per minute through an unblocked suction line. Two types ofsuction control are available. When the "fixed suction" switch 44 isset, the pump will immediately begin pumping at the preset suction ratewhen the control pedal is depressed. When the "linear suction" switch 46is set, the operator can accelerate the suction rate up to the presetrate by controllably depressing the control pedal.

The pump mechanism includes a brushless DC motor and gearbox locatedwithin the module which rotates a pump head 12. Evenly spaced around thepump head are six rollers 14. The pump head is turned in a clockwisedirection by the motor so that the rollers will sequentially andsmoothly squeeze the pump tubing as they pass along the upper quadrantof the pump head location. Included in the pump mechanism is a moreconventional vacuum pump not shown which can alternately be used toreplace the peristaltic pump system. The vacuum pump is akin to thatdescribed in the previously referenced U.S. Pat. No. 4,493,695.

The pump cassette, to be described below, is affixed in an area outlinedby 48. The cassette is supported at the bottom by the placement of tabsat the bottom corners of the cassette in two retaining brackets 20a and20b. The cassette is held in place by a cam bar 18 at the top of thecassette. The cam bar is secured between the sides of a latch 16, whichis pivotally connected to latch supports 17a and 17b above the area 48.When the cassette is placed in position with its tabs located in thebrackets 20a and 20b, the latch may be swung down so that the cam barengages the upper edge of the cassette. The latch is then pressed firmlyagainst the front surface of the cassette, causing the cam bar to rollto the center of the cassette top which presses the suction tubing ofthe cassette against the pump head. The cam bar distributes pressureequally across the top of the mounted cassette.

A second solenoid actuated interrupter bar controllably extends throughopening 28 in the front panel to selectively open or occlude a vent lineto the suction line of the cassette.

Referring to FIGS. 2-4, views of the outside of a cassette 50 suitablefor use with the module 10 are shown. FIG. 2 illustrates the frontsurface 51 of the cassette. The cassette is characterized by an ovalopening 56 which accommodates the pump head. The width and arc of theopening 56 are sized to be just slightly larger than the pump head.

Located at the top of the cassette is an inlet luer 68 of the infusionline. The infusion line exits the cassette through tubing 64. The tubing64 is connected to a barbed fitting within the cassette. This connectionis protected by a molded guard 66 which projects from the front 51 ofthe cassette. The guard 66 is also shown in FIG. 4. The infusion tubing64 terminates in a luer 81, by which the tubing may be connected to theinfusion port of an infusion/aspiration handpiece or a surgical cuttinginstrument.

A suction tubing line 60 has a molded adapter piece 80 connected at itsfree end for connection to the suction, or aspiration, port of thehandpiece or instrument. Tubing 60 is similarly connected to a barbedfitting within the cassette which is protected by a molded guard 62. Thesuction line passes through the cassette and makes a transition to apump tubing segment 58. The tubing segment 58 enters the opening 56through an aperture in the interior wall of the opening, passes alongthe inside wall along its upper arc, and exits the opening through anaperture in the interior wall on the opposite end of the arc from whichit entered. The tubing segment is made of a material suitable for use ina peristaltic pump, such as silicone.

The tubing segment 58 exits the cassette through a hole in the bottom,from which it leads to a means for disposing of aspirated material suchas a drain bag.

Along each vertical side of the cassette 50, the body of the cassette isthinned to form corner tabs 70a and 70b. These corner tabs fit snuglyinto the retaining brackets 20a and 20b of the module 10.

FIG. 3 shows the back surface 53 of the cassette 50, including thepreviously described infusion line inlet luer 68, the opening 56, andpump tubing segment 58. Also shown are an aperture 76 through which theinterrupter bar of opening 26 enters the cassette, and an aperture 78for passage of the interrupter bar of opening 28. A vent line tubingsegment is visible through aperture 78, and an infusion tubing segmentis visible through aperture 76. There is a hole 94 through the back ofthe cassette for passage of a pressure sensing port 82, which mates withthe port 22 when the cassette is mounted on the module 10. The port 82is surrounded by a foam sealing gasket 84.

FIG. 4 is a bottom view of the cassette 50, which is seen to becomprised of a front half 52 and a back half 54. Guards 66 and 62 whichextend from the front surface 51 are shown at the top of the drawing.Aperture 74 is provided for passage of tubing segment 58, which forclarity is not represented in FIG. 4. Aperture 72 is an opening for thevent line. On either side of the cassette bottom the corner tabs 70a and70b may be seen.

Referring to FIG. 5, the interior of the back cassette half 54 is shown,with tubing segments and a junction block 150 drawn in phantom for easeof illustration. The infusion luer 68 enters the top of the cassettethrough a semicircular aperture in a block 90. The block 90 includes arectangular opening 92 which retains a collar of the luer 68 to hold theluer in place. An infusion line tubing segment 140 extends from the luer68 to the junction block 150. The tubing segment 140 passes over theinterrupter bar aperture 76, and is maintained in this position by fourmolded guides 77a-77d. Vent tubing segment 174 extends from the junctionblock 150 to the aperture 72 and passes over the interrupter baraperture 78.

The pump tubing segment 58 is retained in its intended position by amolded upper guide 100 and the opposite ends of a molded lower guide102. A curved, molded protrusion 104 spans the two guides proximate thejunction block 150 to serve as a portion of an integral clamp whichsecures the tubing segment 58 on its junction block fitting. A moldedbracket with holes 106 and 108 at the ends of the location of protrusion104 mates with pins in the front cassette half to secure the integraltubing clamp.

A portion of the upper guide 100 is seen to be contiguous with the upperarc of the opening 56. This portion of the guide serves two furtherpurposes: it forms the upper interior wall of the opening 56, and it isthe surface against which the tubing segment 58 is compressed by thepump head. The central portion of the lower guide 102 similarly iscontiguous with the perimeter of the opening 56, and likewise forms theside and lower arcuate interior walls of the opening. It may be seenthat the spaces between the two guides at their intersections with theopening perimeter form the apertures through which the pump tubingsegment 58 enters and exits the opening 56.

Located at the upper two corners of the back cassette half 54 and justabove each of the tabs 70a and 70b are holes 122 which mate with pins ofthe front cassette half 52.

FIG. 7 shows the interior of the front cassette half 52. A block 90'with an opening 92' mates with block 90 of the back cassette half tocapture the luer 68 and its collar. A protrusion 86 forms an anvilsurface for occluding tubing segment 140. The interrupter bar enteringthe cassette through aperture 76 will squeeze and thereby occlude theinfusion line tubing segment 140 between the interrupter bar and theprotrusion 86. Below the protrusion 86 are two holes through which themolded guards 62 and 66 on the front surface of the cassette may beseen. Below the hole surrounded by guard 62 for the suction line is aprotrusion forming an anvil surface 88. The interrupter bar enteringaperture 78 occludes the vent tubing segment 174 between the protrusion88 and the interrupter bar.

Curved protrusion 114 extends to form the second half of the integralclamp which secures tubing segment 58 on its junction block fitting whenthe two cassette halves are mated together. Pins 110 and 112 fit intoholes 106 and 108 of the molded bracket in the back cassette half tosecure the integral clamp for the pump tubing segment. A protrusion 134fits between the ends of the guides 100 and 102 where the tubing segment58 leaves the two guides.

Located around the upper arc of the opening 56 is a reinforced supportwall 130. The support wall 130 is spaced slightly above the perimeter ofthe opening so that the upper guide 100 of the back cassette half willfit flush against surface 132 of the support wall. The support wall thussupports the upper arcuate portion of the guide 100 where it opposes thecompressive forces of the pump head rollers as the tubing segment 58 iscompressed.

Located at the upper corners of the front cassette half and just abovethe tab locations are pins 120, which mate with the holes 122 in theback cassette half. It may be seen that when the two cassette halves aremated together, they are fastened to each other by the four pins 120,pins 110 and 112, and their respective holes.

FIG. 6 illustrates the cassette tubing segments and junction block whichwere shown in phantom in FIG. 5, and in the same configuration. FIG. 6clearly shows the collar 98 of the infusion line female luer 68 whichfits into the rectangular openings 92, 92' of the cassette halves. Thephantom lines 76' indicate the location of aperture 76 behind theinfusion line tubing segment 140 in an assembled cassette. The infusionline tubing segment 140 is connected to a luer 152 on the junction block150, and the vent tubing segment 174 is connected to a luer 156 on thejunction block. The location of aperture 78 relative to the vent tubingsegment in an assembled cassette is indicated by phantom lines 78'.

The pump tubing segment 58 is connected to a fitting 154 on the junctionblock. The fitting 154 has a narrow diameter neck, about which theintegral clamp of the cassette secures the tubing segment to the fitting154. Barbed fittings 160 and 162 extend normal to the plane of thedrawing for connection to infusion tubing 64 and suction tubing 60. Thefittings 160 and 162 are more clearly shown in FIG. 6a, which is across-sectional view of the junction block 150.

In FIG. 6a, the fluid passageways through the junction block 150 can beseen. A passageway 142 for the infusion line enters the junction blockthrough fitting 152 on the back of the block as it is oriented in FIGURE6a, and continues through the barbed fitting 160. A suction linepassageway 166 passes through the barbed fitting 162 and continuesthrough the fitting 154. The extension of passageway 166 to the bottomof the junction block in FIG. 6a forms the pressure sensing port 82. Thepressure sensing port 82 is surrounded by a raised mounting surface 164for the sealing gasket 84 of FIGURE 3. The diameter of surface 164,shown in phantom in FIG. 6, is sized to just fit into the hole 94 in theback half of the cassette (FIGS. 3 and 5).

FIG. 8 illustrates a side view of the cassette 50 when mounted foroperation on the module 10. The mounted cassette is supported at thebottom by the placement of the corner tabs 70a and 70b in the retainingbrackets 20a and 20b. This placement locates the cassette in its correcthorizontal position on the module so that the cassette can be positionedwith its back surface 53 flush against the front panel 11 of the module.In this position the pump head 12 extends through opening 56. Thecassette is slightly raised from its final vertical alignment, as thetubing segment 58 is resting uncompressed between the pump head 12 andthe guide wall 100.

To lower the cassette to its intended vertical alignment with themodule, the latch 16 is pivoted downward over the cassette. This causesthe cam bar 18 to first contact the upper front edge of the cassette,then to forcibly roll on to the top of the cassette, as shown in FIG. 8.The cam bar 18 thus presses the cassette downward with the corner tabs70a and 70b firmly seated in the retaining brackets, and at the sametime compresses tubing segment 58 between the guide wall 100 and therollers 14 of the pump head 12. The interrupter bar apertures 26 and 28of the module are then aligned with their corresponding apertures 76 and78 on the back of the cassette. The pressure sensing ports 22 and 82 arelikewise aligned.

Alternately, the cassettes 200, 300, 400, 500, as seen in FIGS. 9through 14 can be used as a second preferred embodiment of the cassetteof the present invention. The advantage of these types of cassettes isthat they may be used with both a peristaltic pump system as well as avacuum pump aspiration system. For example, as seen in FIGS. 9, 10 and11, the cassette 200 is used with a peristaltic pump. There are tabs270a and 270b which allow the cassette to be emplaced within the console10 as seen in FIG. 1. Alternatively, cassette 200 may be emplaced withinconsole 900 as seen in FIG. 15, by inserting tabs 270a, 270b into grips910. The pump head 920 then is secured to cassette opening 256.Perpendicular forces are applied to sides 201, 202 of the cassette 200in order to engage and align the cassette 200 with pump head 920 withingrips 910. If latch 930 on console 900 is not securely engaged withcassette port 203 as seen in FIG. 11, a switch within console 900 willdisable pump head 920. Returning to FIG. 1, the grips 17a, 17b and theroller head 214 are modified so that the rollers act along the edge ofthe cassette. The roller heads 214 fit securely within opening 256 ofthe cassette. Between opening 256 and the roller heads 214 is placedpump tubing segment 258, to affect peristaltic pumping. Pump tubingsegment 258 leads out of cassette 200 in order to engage roller heads214, then returns into the cassette 200 finally exiting at aperture 234in order to lead to the disposal bag as seen in FIG. 9.

In addition, the infusion lead 240 enters the cassette 200 at aperture236 and will engage infusion pinch 276. From the infusion pinch 276 theinfusion exit tube 264 leads out of cassette 200 at aperture 238. Beforeengaging the infusion pinch 276, which enters the cassette 200 ataperture 226, the infusion lead 240 enters at T-shaped intersection 250which contains the vent segment 274. The vent segment 274 passes betweenthe vent pinch 278, which enters the cassette 200 at aperture 228. Thevent segment 274 engages the aspiration input lead 260 and the pumpsegment 258 at T-shaped intersection 220.

Turning now to the aspiration input lead 260, it exits the handpiece 300and is guided past the T-shaped intersection 230 where it becomes pumpsegment 258. Pump segment 258 also engages T-shaped intersection 230which leads to sensing 280a. Pump segment 258 continues through thecassette 200 in order to engage peristaltic pump roller heads 214. Pumpsegment 258 then exits the cassette at aperture 234.

Finally, sensing segment 280a leads into filter 210 and through port 292and seal 294 into sensor 282. Sensor 282 is able to determine thepumping pressure that the roller heads 214 are exerting on the pumpsegment 258. Roller heads 214 can therefore be adjusted to obtain thecorrect amount of pumping. In addition, vent segment 274 is able to ventpure fluid from the infusion line 240 to the aspiration line 260.

It will be noticed that the cassette 200 as constructed in theembodiment shown in FIGS. 9, 10 and 11, has two distinct advantages.First, the interaction between any irrigation/aspiration module and thecassette 200 takes place in the same plane. This creates less stress onthe cassette and the irrigation or aspiration lines, and decreases thepossibility of excess forces and moments. In addition, it makes latchingand unlatching the cassette easier. Also, it will be noticed thatbecause the roller heads 214 engage only a small arc of the pump segment258, lesser forces are exerted on the pump segment 258. This ease ofemplacement and reduction of forces makes the use of this secondembodiment of the cassette 200 highly desirable.

The cassette of the present invention can be modified so that theoccludable openings of the console 10 or console 900 can be used. Asseen in FIG. 12, infusion pinch 376 enters the cassette 300 throughaperture 326, which lies on the bottom of the cassette 300. Also, ventpinch 378 lies underneath the cassette 300 and enters through aperture328. Similarly, sensor 382 lies underneath cassette 300 and line 280bexits the cassette at port 392. A plunger 394 as seen in FIG. 15 isinserted into port 392. The plunger 394 serves to seal sensing line 280bleading to sensor 382. Plunger 394 when inserted into port 392 alsoserves to latch cassette 300 to console 900. Thus, in this embodiment,the planes of the tubing lines will turn at 90° angles.

While the function of the cassette will operate identically, thebenefits obtained by operating in a single plane are not apparent. Thatis, again, infusion line 264 engages T-shaped intersection 250 in orderto lead to infusion exit 264. Also engaging T-shaped intersection 250 isvent segment 274, which leads to aspiration input 260 at T-shapedintersection 220. Aspiration input line 260 enters the cassette 300 ataperture 234 and leads into pump segment 258 which engages roller heads214 at arc-shaped exterior 256 of the cassette 300. Again, sensing line280a exits the aspiration line 260 at T-shaped intersection 230, andleads through filter 210 to sensor 382. Pumping is adjusted at thesensor 382.

It is possible to use the second preferred embodiment of the presentcassette in a vacuum tubing system. As seen in FIG. 13, cassette 400 hasbeen so modified. Infusion line 240 enters cassette 400 at aperture 236.Infusion line 240 then engages T-shaped intersection 250 to lead toinfusion exit line 246. Infusion exit line 246 then leads to hand piece300. Infusion exit line 246 can be pinched at infusion pinch 276 whichengages the cassette 400 at aperture 226. Also leading from T-shapedintersection 250 is vent segment 274, which encounters vent pinch 278engaging the cassette 400 at aperture 228. Vent 274 leads from infusionline 240 to the aspiration input line 260, which it engages at T-shapedintersection 230. Aspiration input line 260 enters the cassette ataperture 234 and engages T-shaped intersection 230.

Of course, because peristaltic pumping is not being used, there must bean adaptation made in the cassette 400 to engage the vacuum pump of thepresent system. This is evident is semicircular fitting 450. Thissemicircular fitting 450 fits within the arc-shaped section 256 of thecassette 400 in order to engage the cassette 400 and the aspirationline. Semicircular fitting 450 is an adapted part of refuse jar 410 ascommonly disclosed in all vacuum pump type systems. Therefore, refusejar 410 will receive the refuse from aspiration line 258a so thataspiration line 258b will be clear of refuse. Again, aspiration line258b will lead into filter 210 so that suction sensing line 280 will beclear of refuse.

Suction sensing line 280 will lead to a sensor not shown, in order toregulate pump 482. There is a sensor pinch at 484 which enters thecassette 400 at aperture 486. This aperture 486 is able to close thesuction sensing line 280 and pump line 258b in order to stop pumpingwithin the aspiration line 258b. It is to be noticed that again,pumping, infusion and aspiration take place in the same plane along thecassette 400.

Finally, if it is desired to use the cassette of the present inventionwith a air vent as disclosed in previous systems, this embodiment ispossible as seen in FIGURE 14. There, cassette 500 contains infusionline 240 which enters the cassette at aperture 236. The infusion line240 leads into fitting 560, which has been attached to cassette 500. Onthis attachment 560, the infusion line 240 encounters infusion pinch 576which enters the attachment 560 at aperture 526. Infusion 240 then exitsthe cassette 500 at aperture 234, and leads to hand piece 300.Aspiration line 260 also enters the cassette at aperture 234 and willflow into T-shaped intersection 520. The aspiration line 260 can be thenvented to air through air vent 580. The aspiration line 260 leads fromT-shaped intersection 520 to aspiration exit line 258. This line 258continues through arc-shaped exterior wall 256, then throughsemicircular fitting 450 and into fitting 560. Aspiration pinch 584enters fitting 560 at aperture 528. The aspiration line 258 thereforereturns into the cassette 500 and leads into jar 410 through the bottomof the cassette 500. Pumping line 580 leads from jar 410 through filter510 and to pump 582.

The pump cassette systems in any of the embodiments are now ready foroperation. As best seen in the system described in FIG. 1, the user setsthe preset vacuum level with the knob 32 and its units of display withthe knob 36. The suction rate is set by pressing one of pushbuttons 30,and the mode of suction control is set by setting one of switches 44 and46. In the system where vacuum pumping is possible, a modification ismade to the console to include vacuum pumping. The infusion line may becontrolled automatically by depressing pushbutton 42c, or pushbutton 42amay be pressed to close the infusion line until it is needed.

The fluid line is connected by connecting a source of infusion liquid tothe female luer 68. Generally, this will be a bag or bottle of liquidsuspended above the module, as seen in FIG. 9. Luer 81 and adapter 80 oftubing lines 64 and 60 are connected to the infusion and suction portsof the handpiece or surgical instrument, and the system may then beprimed with liquid.

In operation with automatic infusion line control, where the controlpedal is depressed the infusion line interrupter bar retracts to openthe infusion line tubing segment. This occlusion control technique isthe same as that used by the interrupter bars described in U.S. Pat. No.4,493,695. Infusion liquid then flows through tubing segment 140, thejunction block passageway 142, the barbed luer 160, and into theinfusion tubing 64. Infusion is effected in the same fashion insubsequent embodiments.

Further depression of the control pedal causes the pump head to beginrotating, either immediately at its selected rate when fixed suction isset, or at a controlled accelerating rate to the selected rate if linearsuction is called for. Suction then begins to build in the suction line60, and is continuously monitored at the port 82 of the junction blockby the module's internal pressure sensor. All the peristaltic pumpsoperate in the same fashion.

The pump head continues to rotate so long as the pump is freely pumpingliquid. When the actual vacuum level reaches the preset vacuum level, aswould occur if the suction port of the instrument or handpiece becomesfully occluded with particles of tissue, the pump head rotation stopsuntil the actual vacuum level falls to a predetermined level, such as80% of the preset maximum level. At this point the pump head resumes itsrotation to aspirate the tissue particles through the suction line andaway from the surgical site. Thus, there is no buildup of substantialsuction pressure at the handpiece or instrument tip until an occlusionof the suction line occurs. This prevents the application of undesiredsuction pressures to the patient at the surgical site, and eliminatesany tendency of the hand-held instrument to "grab" tissue, as wouldhappen if continual suction were applied. The physician thus is moreeasily able to precisely control the instrument during the surgicalprocedure.

On the other hand, if vacuum pumping is desired, cassette 200 may beused as modified and seen in FIGURES 13 and 14 with cassettes 400, 500.While the infusion line operates identically as in the peristalticsystem, the aspiration line will operate in the same way disclosed inU.S. Pat. No. 4,493,695. Of course, other than as disclosed withcassette 500, all the present embodiments are vented in fluidcommunication between the infusion and aspiration line.

When the depressed control pedal is released by the physician, theinfusion segment 140 is occluded and the interrupter bar extendingthrough aperture 78 of the cassette is momentarily retracted, openingthe vent segment 174 and equalizing the suction line vacuum toatmospheric pressure. The handpiece or instrument can then be movedabout the surgical site without exposing the patient to any residualvacuum pressures in the suction line.

What is claimed is:
 1. A microsurgical irrigation/aspiration system,comprising:a control system including:(i) means for mounting adisposable cassette; (ii) means for selectably occluding an infusionline; and (iii) means for pumping a fluid, wherein said pumping means ischosen from the group consisting of peristaltic pumping mean and vacuumpumping means; and a disposable cassette, adpated for mounting on saidcontrol system so as to engage said pumping means and said selectablyoccluding means, and including;(i) a selectably occludable infusionline, operable in conjunction with said selectably occluding means; (ii)means for connecting said infusion line to a solution source; (iii) apumping segment suitable for engagement with and capable of operation bysaid pumping means such that said pumping means, when engaged with saidpumping segment is capable of the performance of either peristalicpumping or vacuum pumping through said pumping segment; and (iv) meansfor connecting said pumping segment to a solution container; whereinwhen said pumping means performs vacuum pumping, said vacuum pumping isaccomplished outside said cassette.
 2. A microsurgicalirrigation/aspriation system of claim 1 wherein said cassette furtherincludes a suction sensing port and a vent segment in liquidcommunication with said pumping segment; and wherein said control meansfurther includes a sensor, means for selectively occluding said ventsegment and means for connecting said sensor in liquid communicationwith said suction sensing port.
 3. The system of claim 1 wherein controlmeans comprises an outermost panel and said pumping means comprisesroller head means, extending from said outermost panel, for performingperistaltic pumping; andsaid cassette contains a wall with an arcuatesurface where said cassette engages said roller head means and saidpumping segment emplaced between said roller head means and said arcuatesurface of said cassette when said cassette engages said roller headmeans.
 4. The system of claim 3 wherein said control means furtherincludes means for securing said cassette on said control means withsaid pumping segment compressed between said roller head means and saidarcuate surface.
 5. The system of claim 4 wherein said control meansfurther includes means for selectively occluding said infusion line. 6.The system of claim 5, wherein said cassette further includes a suctionsensing port and a vent segment in liquid communication with saidpumping segment; andwherein said console further includes a sensor,means for selectively occluding said vent segment and means forconnecting said sensor in liquid communication with said suction sensingport.